L-Lysine is an essential amino acid that must be obtained through the diet or through supplementation. Lysine is necessary for the production of all proteins in the body, and is required for the maintenance of the structural proteins collagen and elastin, which form all connective tissue such as skin, tendon, and bone. L-Lysine is also a precursor to L-carnitine, which is needed for fat metabolism and energy production, which can support good health. In addition, L-Lysine supports a healthy immune system helping to fight cold sores. This double strength 1000mg tablet is ideal for tougher and recurring cold sore sufferers, and those dealing with more serious concerns of bone health and family history of osteoporosis.